From patchwork Thu Nov 9 06:57:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 10050251 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0066F603FF for ; Thu, 9 Nov 2017 06:57:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E31F82AB38 for ; Thu, 9 Nov 2017 06:57:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D7FA32AB3B; Thu, 9 Nov 2017 06:57:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 455242AB3A for ; Thu, 9 Nov 2017 06:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752554AbdKIG5O (ORCPT ); Thu, 9 Nov 2017 01:57:14 -0500 Received: from esa4.hgst.iphmx.com ([216.71.154.42]:29572 "EHLO esa4.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752431AbdKIG5N (ORCPT ); Thu, 9 Nov 2017 01:57:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1510210634; x=1541746634; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=QfL0gajhvUDo70GcnwwT/r37Ltskg2/zB1aeM4qYr+Y=; b=c9abGz3FrECnDDuRYjGEdyk+0RCEOjCllmZMSnQ7QBu+uNir2aQ119w0 Smf1VOQUEfWzK4KjZIKtXdy8BlCU9zjkdB9/C312JJMxS+W9mpEPo9DDZ OMnXDCvRXhBQTg3jqkk5JDuiMdvzjmMdZ+xJSIjO68J94Zdp4NWGoZrBF hb8Ubx/e8oLOz4cKFB7OEF5LqCviLF2J0yANNj0d0RgXERstt2Zg/fNuB Cbdpf2ZSy2+0DtvXqwgxJ/z1ZTPHUT7EitOeuE+TLUUfHFYbm5jZCeKX5 g43XWbVm+zO304vOsETwZ7XexqweMXKc67VP9aOV/2B/LUCCE2X5Ze6xG Q==; X-IronPort-AV: E=Sophos;i="5.44,368,1505750400"; d="scan'208";a="61715389" Received: from sjappemgw11.hgst.com (HELO sjappemgw12.hgst.com) ([199.255.44.62]) by ob1.hgst.iphmx.com with ESMTP; 09 Nov 2017 14:57:13 +0800 Received: from washi.fujisawa.hgst.com ([10.149.53.254]) by sjappemgw12.hgst.com with ESMTP; 08 Nov 2017 22:57:11 -0800 From: Damien Le Moal To: linux-scsi@vger.kernel.org, "Martin K . Petersen" , linux-block@vger.kernel.org, Jens Axboe Cc: Christoph Hellwig , Bart Van Assche Subject: [PATCH V8 1/7] block: introduce zoned block devices zone write locking Date: Thu, 9 Nov 2017 15:57:01 +0900 Message-Id: <20171109065707.17210-2-damien.lemoal@wdc.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20171109065707.17210-1-damien.lemoal@wdc.com> References: <20171109065707.17210-1-damien.lemoal@wdc.com> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Components relying only on the request_queue structure for accessing block devices (e.g. I/O schedulers) have a limited knowledged of the device characteristics. In particular, the device capacity cannot be easily discovered, which for a zoned block device also result in the inability to easily know the number of zones of the device (the zone size is indicated by the chunk_sectors field of the queue limits). Introduce the nr_zones field to the request_queue structure to simplify access to this information. Also, add the bitmap seq_zone_bitmap which indicates which zones of the device are sequential zones (write preferred or write required) and the bitmap seq_zones_wlock which indicates if a zone is write locked, that is, if a write request targeting a zone was dispatched to the device. These fields are initialized by the low level block device driver (sd.c for ZBC/ZAC disks). They are not initialized by stacking drivers (device mappers) handling zoned block devices (e.g. dm-linear). Using this, I/O schedulers can introduce zone write locking to control request dispatching to a zoned block device and avoid write request reordering by limiting to at most a single write request per zone outside of the scheduler at any time. Based on previous patches from Damien Le Moal. Signed-off-by: Christoph Hellwig [Damien] * Fixed comments and identation in blkdev.h * Changed helper functions * Fixed this commit message Signed-off-by: Damien Le Moal Reviewed-by: Martin K. Petersen --- block/blk-core.c | 1 + block/blk-zoned.c | 42 +++++++++++++++++++ include/linux/blkdev.h | 111 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 154 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index b8d1aa2d1008..e887c0b45d0b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1555,6 +1555,7 @@ void __blk_put_request(struct request_queue *q, struct request *req) lockdep_assert_held(q->queue_lock); + blk_req_zone_write_unlock(req); blk_pm_put_request(req); elv_completed_request(q, req); diff --git a/block/blk-zoned.c b/block/blk-zoned.c index ff57fb51b338..acb7252c7e81 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -22,6 +22,48 @@ static inline sector_t blk_zone_start(struct request_queue *q, } /* + * Return true if a request is a write requests that needs zone write locking. + */ +bool blk_req_needs_zone_write_lock(struct request *rq) +{ + if (!rq->q->seq_zones_wlock) + return false; + + if (blk_rq_is_passthrough(rq)) + return false; + + switch (req_op(rq)) { + case REQ_OP_WRITE_ZEROES: + case REQ_OP_WRITE_SAME: + case REQ_OP_WRITE: + return blk_rq_zone_is_seq(rq); + default: + return false; + } +} +EXPORT_SYMBOL_GPL(blk_req_needs_zone_write_lock); + +void __blk_req_zone_write_lock(struct request *rq) +{ + if (WARN_ON_ONCE(test_and_set_bit(blk_rq_zone_no(rq), + rq->q->seq_zones_wlock))) + return; + + WARN_ON_ONCE(rq->rq_flags & RQF_ZONE_WRITE_LOCKED); + rq->rq_flags |= RQF_ZONE_WRITE_LOCKED; +} +EXPORT_SYMBOL_GPL(__blk_req_zone_write_lock); + +void __blk_req_zone_write_unlock(struct request *rq) +{ + rq->rq_flags &= ~RQF_ZONE_WRITE_LOCKED; + if (rq->q->seq_zones_wlock) + WARN_ON_ONCE(!test_and_clear_bit(blk_rq_zone_no(rq), + rq->q->seq_zones_wlock)); +} +EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock); + +/* * Check that a zone report belongs to the partition. * If yes, fix its start sector and write pointer, copy it in the * zone information array and return true. Return false otherwise. diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 225617dd0a3f..1c715dae31e4 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -120,6 +120,8 @@ typedef __u32 __bitwise req_flags_t; /* Look at ->special_vec for the actual data payload instead of the bio chain. */ #define RQF_SPECIAL_PAYLOAD ((__force req_flags_t)(1 << 18)) +/* The per-zone write lock is held for this request */ +#define RQF_ZONE_WRITE_LOCKED ((__force req_flags_t)(1 << 19)) /* flags that prevent us from merging requests: */ #define RQF_NOMERGE_FLAGS \ @@ -546,6 +548,22 @@ struct request_queue { struct queue_limits limits; /* + * Zoned block device information for request dispatch control. + * nr_zones is the total number of zones of the device. This is always + * 0 for regular block devices. seq_zones_bitmap is a bitmap of nr_zones + * bits which indicates if a zone is conventional (bit clear) or + * sequential (bit set). seq_zones_wlock is a bitmap of nr_zones + * bits which indicates if a zone is write locked, that is, if a write + * request targeting the zone was dispatched. All three fields are + * initialized by the low level device driver (e.g. scsi/sd.c). + * Stacking drivers (device mappers) may or may not initialize + * these fields. + */ + unsigned int nr_zones; + unsigned long *seq_zones_bitmap; + unsigned long *seq_zones_wlock; + + /* * sg stuff */ unsigned int sg_timeout; @@ -783,6 +801,27 @@ static inline unsigned int blk_queue_zone_sectors(struct request_queue *q) return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0; } +static inline unsigned int blk_queue_nr_zones(struct request_queue *q) +{ + return q->nr_zones; +} + +static inline unsigned int blk_queue_zone_no(struct request_queue *q, + sector_t sector) +{ + if (!blk_queue_is_zoned(q)) + return 0; + return sector >> ilog2(q->limits.chunk_sectors); +} + +static inline bool blk_queue_zone_is_seq(struct request_queue *q, + sector_t sector) +{ + if (!blk_queue_is_zoned(q) || !q->seq_zones_bitmap) + return false; + return test_bit(blk_queue_zone_no(q, sector), q->seq_zones_bitmap); +} + static inline bool rq_is_sync(struct request *rq) { return op_is_sync(rq->cmd_flags); @@ -1019,6 +1058,16 @@ static inline unsigned int blk_rq_cur_sectors(const struct request *rq) return blk_rq_cur_bytes(rq) >> 9; } +static inline unsigned int blk_rq_zone_no(struct request *rq) +{ + return blk_queue_zone_no(rq->q, blk_rq_pos(rq)); +} + +static inline unsigned int blk_rq_zone_is_seq(struct request *rq) +{ + return blk_queue_zone_is_seq(rq->q, blk_rq_pos(rq)); +} + /* * Some commands like WRITE SAME have a payload or data transfer size which * is different from the size of the request. Any driver that supports such @@ -1568,7 +1617,15 @@ static inline unsigned int bdev_zone_sectors(struct block_device *bdev) if (q) return blk_queue_zone_sectors(q); + return 0; +} +static inline unsigned int bdev_nr_zones(struct block_device *bdev) +{ + struct request_queue *q = bdev_get_queue(bdev); + + if (q) + return blk_queue_nr_zones(q); return 0; } @@ -1944,6 +2001,60 @@ extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int, extern int bdev_read_page(struct block_device *, sector_t, struct page *); extern int bdev_write_page(struct block_device *, sector_t, struct page *, struct writeback_control *); + +#ifdef CONFIG_BLK_DEV_ZONED +bool blk_req_needs_zone_write_lock(struct request *rq); +void __blk_req_zone_write_lock(struct request *rq); +void __blk_req_zone_write_unlock(struct request *rq); + +static inline void blk_req_zone_write_lock(struct request *rq) +{ + if (blk_req_needs_zone_write_lock(rq)) + __blk_req_zone_write_lock(rq); +} + +static inline void blk_req_zone_write_unlock(struct request *rq) +{ + if (rq->rq_flags & RQF_ZONE_WRITE_LOCKED) + __blk_req_zone_write_unlock(rq); +} + +static inline bool blk_req_zone_is_write_locked(struct request *rq) +{ + return rq->q->seq_zones_wlock && + test_bit(blk_rq_zone_no(rq), rq->q->seq_zones_wlock); +} + +static inline bool blk_req_can_dispatch_to_zone(struct request *rq) +{ + if (!blk_req_needs_zone_write_lock(rq)) + return true; + return !blk_req_zone_is_write_locked(rq); +} +#else +static inline bool blk_req_needs_zone_write_lock(struct request *rq) +{ + return false; +} + +static inline void blk_req_zone_write_lock(struct request *rq) +{ +} + +static inline void blk_req_zone_write_unlock(struct request *rq) +{ +} +static inline bool blk_req_zone_is_write_locked(struct request *rq) +{ + return false; +} + +static inline bool blk_req_can_dispatch_to_zone(struct request *rq) +{ + return true; +} +#endif /* CONFIG_BLK_DEV_ZONED */ + #else /* CONFIG_BLOCK */ struct block_device;